// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/macros.h"
#include "base/process/process_metrics.h"

#include <stddef.h>
#include <stdint.h>
#include <sys/param.h>
#include <sys/sysctl.h>

namespace base {

// static
ProcessMetrics* ProcessMetrics::CreateProcessMetrics(ProcessHandle process)
{
    return new ProcessMetrics(process);
}

size_t ProcessMetrics::GetPagefileUsage() const
{
    struct kinfo_proc info;
    size_t length;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_,
        sizeof(struct kinfo_proc), 0 };

    if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
        return -1;

    mib[5] = (length / sizeof(struct kinfo_proc));

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return -1;

    return (info.p_vm_tsize + info.p_vm_dsize + info.p_vm_ssize);
}

size_t ProcessMetrics::GetPeakPagefileUsage() const
{
    return 0;
}

size_t ProcessMetrics::GetWorkingSetSize() const
{
    struct kinfo_proc info;
    size_t length;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_,
        sizeof(struct kinfo_proc), 0 };

    if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
        return -1;

    mib[5] = (length / sizeof(struct kinfo_proc));

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return -1;

    return info.p_vm_rssize * getpagesize();
}

size_t ProcessMetrics::GetPeakWorkingSetSize() const
{
    return 0;
}

bool ProcessMetrics::GetMemoryBytes(size_t* private_bytes,
    size_t* shared_bytes)
{
    WorkingSetKBytes ws_usage;

    if (!GetWorkingSetKBytes(&ws_usage))
        return false;

    if (private_bytes)
        *private_bytes = ws_usage.priv << 10;

    if (shared_bytes)
        *shared_bytes = ws_usage.shared * 1024;

    return true;
}

bool ProcessMetrics::GetWorkingSetKBytes(WorkingSetKBytes* ws_usage) const
{
    // TODO(bapt): be sure we can't be precise
    size_t priv = GetWorkingSetSize();
    if (!priv)
        return false;
    ws_usage->priv = priv / 1024;
    ws_usage->shareable = 0;
    ws_usage->shared = 0;

    return true;
}

bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const
{
    return false;
}

static int GetProcessCPU(pid_t pid)
{
    struct kinfo_proc info;
    size_t length;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, pid,
        sizeof(struct kinfo_proc), 0 };

    if (sysctl(mib, arraysize(mib), NULL, &length, NULL, 0) < 0)
        return -1;

    mib[5] = (length / sizeof(struct kinfo_proc));

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return 0;

    return info.p_pctcpu;
}

double ProcessMetrics::GetCPUUsage()
{
    TimeTicks time = TimeTicks::Now();

    if (last_cpu_ == 0) {
        // First call, just set the last values.
        last_cpu_time_ = time;
        last_cpu_ = GetProcessCPU(process_);
        return 0;
    }

    int64_t time_delta = (time - last_cpu_time_).InMicroseconds();
    DCHECK_NE(time_delta, 0);

    if (time_delta == 0)
        return 0;

    int cpu = GetProcessCPU(process_);

    last_cpu_time_ = time;
    last_cpu_ = cpu;

    double percentage = static_cast<double>((cpu * 100.0) / FSCALE);

    return percentage;
}

ProcessMetrics::ProcessMetrics(ProcessHandle process)
    : process_(process)
    , last_system_time_(0)
    , last_cpu_(0)
{

    processor_count_ = base::SysInfo::NumberOfProcessors();
}

size_t GetSystemCommitCharge()
{
    int mib[] = { CTL_VM, VM_METER };
    int pagesize;
    struct vmtotal vmtotal;
    unsigned long mem_total, mem_free, mem_inactive;
    size_t len = sizeof(vmtotal);

    if (sysctl(mib, arraysize(mib), &vmtotal, &len, NULL, 0) < 0)
        return 0;

    mem_total = vmtotal.t_vm;
    mem_free = vmtotal.t_free;
    mem_inactive = vmtotal.t_vm - vmtotal.t_avm;

    pagesize = getpagesize();

    return mem_total - (mem_free * pagesize) - (mem_inactive * pagesize);
}

} // namespace base
